Claude Bernard, 1813--1878

31 Oct 1997 13:23

Bernard's three great claims on posterity are that he was one of the founders
of proper, experimental physiology; that he was, if not the first, then one of
the first to recognize the importance of the "internal environment" of the
organism; and that he was an
excellent methodologist.

In physiology, much that he insisted upon --- experimentation, careful
checking, controls, the application of physics and chemistry --- now seems
obvious, but it met with a fair degree of opposition, some of it from people
who thought that if you just observed nature without interference she'd give up
her secrets, some of it from people who felt experimenting on animals was
cruel. (These latter included Bernard's wife, which did not make for a happy
home life, but did tend to keep him, productively, in the laboratory.) I think
it's safe to say that no one worth arguing with would claim that a Goethian
biology has much going for it, so Bernard won on that score, at least; and
we're still arguing about animal experimentation. (Bernard, incidentally, was
not strictly a materialist, as he was accused of being, since he allowed some
special properties to living things, having to do with their being
"harmonious," but insisted that they had to obey all the usual laws of physics
and chemistry just the same. One wonders what he would have made
of liquid crystals.)

Bernard seems to have been led to the idea of the internal environment by
one of his methodological pillars, which was strict determinism. Yet, as the
First Harvard Law of Behaviorism states, "Under precisely controlled
experimental conditions, the test animal does as it damn well pleases." The
obvious solution is that the determining conditions are not all in the exterior
of the animal, but on the inside as well --- the condition of its blood,
hormone levels, internal temperature, etc., etc. through most of the contents
of Physiology 1. If mechanisms exist to keep the internal environment
constant, you can snap your fingers at changes wrought on the external
environment. As he famously said, "The fixity of the internal environment is
the condition for free life." (This is often quoted without a source or an
original, which I find annoying, so here is mine: La fixité du
milieu intérieur est la condition de la vie
libre; Oevures xvi, 113 = Phénomènes de
la vie, tome i, cited in J. M. D. Olmstead, Claude Bernard,
Physiologist (NY: Harper & Brothers, 1938), p. 254.) This idea,
without which, as I've said, most of what organisms do hardly makes sense, is
obviously very useful to biology, especially in its more developed form, as the
notion of "homeostasis", and it was also one of the roots of the modern notion
of feedback, and so of cybernetics, at least in
its early days when it was worthwhile. It is through this route that he
influenced Herbert Simon's notion of an artifact,
though apparently only indirect, since I can find no mention of Bernard
in The Sciences of the Artificial.

One might call homeostatic devices "Bernard Machines", by analogy with
Turing, von Neumann
and Darwin Machines, and it would be
interesting to know if there are adaptors which
are neither Bernard Machines nor Darwin Machines. (I've heard it suggested
that Bernard Machines are a special case of Darwin Machines, with deviations
from the stable regions being treated as varieties which are selected against,
but I don't think this works, since variation would have to always be in the
direction of higher fitness, and that's against the rules. The difference
between positive and negative feedbacks is also important here, I think.)

Finally, his methodology was
broadly positivist and, I think, broadly correct;
perhaps more importantly, it seems to be the sort of thing scientists
spontaneously develop. Ideas should be formulated in such a way that they can
be subjected to experimental tests; which tests, if properly and stringently
conducted, can suffice to rule out hypotheses, but never definitely establish
them. (Popper, in our own day, has been emphatic on
the importance of this point.) The purpose of experiment and observation is to
test hypotheses, and so the hypothesis is logically prior to the observation.
Induction plays no role in this; hypotheses may be suggested by whatever one
likes, and the connection of a hypothesis with its experimental consequences is
a matter of deductive logic (including mathematics) alone. (In fact, Mills's
canons of induction, for instance, look a lot more like rules for testing
hypotheses than for arriving at them.) Strict determinism he regarded as
essential to science, and while it's certainly a useful guiding assumption, it
cannot be maintained all the time, in which case we must fall back on
statistics. Bernard, it must be said, did not trust statistics at all; whether
this was justified in view of the state of the art, or whether he just didn't
understand them properly, I couldn't say. (He does, however, have some very
amusing passages against stupid uses of statistics in biology.) Outside the
circle of experimental ideas lie mere formal truths (and falsehoods), things
which are true (or false) by virtue of the way we have agreed to use signs, and
purely metaphysical ideas, for which we can never have good grounds to give or
withhold assent. (I hasten to add that Bernard always expressed the high
respect for certain metaphysicians, especially Descartes, and regarded
contemplating metaphysics as a useful mental exercise; i.e. he did not go so
far as the logicial positivists and
declare the whole lot rubbish, though this seems to have been more a matter of
temperament than anything else.)

As I said, this is a view of scientific method that scientists, especially
experimenters, tend to quite naturally, at least in their day-to-day work, even
if they've been taught some other methodology, and will repeat that to you when
you ask them about method explicitly. I think this is significant, though it
hardly means that it's right, since scientists may be at least as prone to
self-delusion as, say, poets or politicians, who are notorious for not
understanding what they are doing. I can't resist thinking, however, that
Bernard had grabbed hold to some essentially right notions about how to do
science --- though I can't think of an experimental test for this.

Recommended:

Claude Bernard, Introduction to the Study of Experimental
Medicine [The only book of his readily available in English; fortunately
it lets one examine all three aspects of his most important work. The English
translation dates from 1927, so it should be public domain soon, and it would
be a very good thing to have on-line.
The French original has, of
course, long since become public domain, but really, who reads French?]

Leszek Kolakowski, History of
Positivist Philosophy [Has a good section on Bernard as a methodologist
and his relation to other, contemporary positivists, including the Comtians.]

Jerome Tarshis, Claude Bernard; Father of Experimental
Medicine [Not an especially wonderful biography, but it does give all
the facts, and is good at explaining what Bernard was up to in lay terms.]

Reino Virtanen, Claude Bernard and His Place in the History
of Ideas

To read:

Lectures on the Phenomena of Life Common to Animals and Plants. [1974 reprint of an 19th century translation]

Frederic Lawrence Holmes, Claude Bernard and animal chemistry

J. Scott Turner, The Tinkerer's Accomplice: How Design
Emerges From Life Itself [Apparently talks about "Bernard machines",
which I thought was a phrase I coined here! — Apparently I did.]